JP7814465B2 - Contention resolution in random access procedures - Google Patents

Description

Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to an apparatus, method, and computer-readable storage medium for contention resolution in random access procedures.

A variety of wireless cellular communication systems have been implemented and are being implemented. Mobile communication systems have been developed and are being developed to meet the increasing demand for communication services. Rapid advances in technology have enabled mobile communication systems to evolve to the point where they can provide high-speed data communication services beyond the voice-centric services of the early days.

A random access (RA) procedure refers to a procedure by which a terminal device establishes or re-establishes a connection with a network device, such as an Evolved NodeB (eNB) or a 5G gNodeB (gNB). A contention-based random access procedure may facilitate the possibility that multiple communication devices may be interested in attempting to access the network device via an RA procedure at the same or similar time. Once access is established and/or confirmed, the network device may allocate resources to the particular terminal device to support uplink communications with the network device.

In general, the example embodiments of the present disclosure provide a solution for contention resolution in random access procedures.

In a first aspect, an apparatus is provided. The apparatus includes at least one processor and at least one memory containing computer program code, the at least one memory and the computer program code configured, by the at least one processor, to cause the apparatus to: send a random access request to a second device, the random access request including a random access preamble for a random access procedure and an identifier of the device; receive control information from the second device on a control channel addressed to the identifier, the control information indicating at least one of resource and timing information for communication between the apparatus and the second device; and determine a result of the random access procedure based at least in part on the control information.

In a second aspect, an apparatus is provided. The apparatus comprises at least one processor and at least one memory containing computer program code, the at least one memory and the computer program code configured, by the at least one processor, to cause the apparatus to: receive a random access request from a second device, the random access request including a random access preamble for a random access procedure and an identifier of the second device; determine, in response to the random access request, control information indicating at least one of resource and timing information for communication between the apparatus and the second device; and transmit, to the second device, the control information on a control channel addressed to the identifier.

In a third aspect, a method is provided. The method includes, in an apparatus, transmitting a random access request to a second apparatus, the random access request including a random access preamble for a random access procedure and an identifier of the apparatus; receiving control information from the second apparatus on a control channel addressed to the identifier, the control information indicating at least one of resource and timing information for communication between the apparatus and the second apparatus; and determining a result of the random access procedure based at least in part on the control information.

In a fourth aspect, a method is provided. The method includes: receiving, at an apparatus, a random access request from a second apparatus, the random access request including a random access preamble for a random access procedure and an identifier of the second apparatus; determining, in response to the random access request, control information indicating at least one of resource and timing information for communication between the apparatus and the second apparatus; and transmitting, to the second apparatus, the control information on a control channel addressed to the identifier.

In a fifth aspect, an apparatus is provided. The apparatus includes: means for transmitting a random access request to a second apparatus, the random access request including a random access preamble for a random access procedure and an identifier of the apparatus; means for receiving control information from the second apparatus on a control channel addressed to the identifier, the control information indicating at least one of resource and timing information for communication between the apparatus and the second apparatus; and means for determining a result of the random access procedure based at least in part on the control information.

In a sixth aspect, an apparatus is provided. The apparatus includes: means for receiving a random access request from a second apparatus, the random access request including a random access preamble for a random access procedure and an identifier of the second apparatus; means for determining, in response to the random access request, control information indicating at least one of resource and timing information for communication between the apparatus and the second apparatus; and means for transmitting, to the second apparatus, the control information on a control channel addressed to the identifier.

In a seventh aspect, there is provided a non-transitory computer-readable medium comprising program instructions for causing an apparatus to perform at least the method according to the third aspect.

In an eighth aspect, there is provided a non-transitory computer-readable medium comprising program instructions for causing an apparatus to perform at least the method according to the fourth aspect.

It should be understood that the Summary section is not intended to identify key or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become readily apparent through the following description.

Some illustrative embodiments will now be described with reference to the accompanying drawings.

FIG. 1 illustrates an exemplary communication network in which embodiments of the present disclosure may be implemented. 10A and 10B are flowcharts illustrating an exemplary random access procedure. 1 is a flowchart illustrating a process for conflict resolution in an RA procedure according to some example embodiments of the present disclosure. FIG. 1 is a schematic diagram illustrating a TAC MAC CE according to some example embodiments of the present disclosure. 1 is a flowchart of a method according to some example embodiments of the present disclosure. 1 is a flowchart of a method according to some example embodiments of the present disclosure. FIG. 1 is a simplified block diagram of a device suitable for practicing embodiments of the present disclosure. 1 is a block diagram of an example computer-readable medium according to some embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numbers represent the same or similar elements.

The principles of the present disclosure will now be described with reference to several exemplary embodiments. It should be understood that these embodiments are set forth for illustrative purposes only, to aid those skilled in the art in understanding and practicing the present disclosure, without implying any limitation on the scope of the present disclosure. The present disclosure described herein can be embodied in various ways other than those described below.

In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

In this disclosure, references to "one embodiment," "an embodiment," "an example embodiment," and the like indicate that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments necessarily include the particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with one embodiment, it is submitted that this applies, within the knowledge of one skilled in the art, to such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described.

Although terms such as "first" and "second" may be used herein to describe various elements, it should be understood that these elements are not limited by these terms. These terms are used only to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of the example embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. Furthermore, it will be understood that the words "comprises," "comprising," "has," "having," "includes," and/or "including," when used herein, specify the presence of stated features, elements, and/or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and/or combinations thereof.

As used in this application, the term "circuitry" means
(a) hardware-only circuit implementations (e.g., implementations using only analog and/or digital circuitry);
(b) A combination of hardware circuitry and software, such as (where applicable):
(i) a combination of analog and/or digital hardware circuitry(s) and software/firmware; and (ii) a hardware processor(s) with software (including digital signal processor(s)), software, and any portion of memory(s) that cooperate to cause a device, such as a mobile phone or server, to perform various functions; and
(c) may refer to one or more, or all, hardware circuit(s) and/or processor(s), such as microprocessor(s) or portions of microprocessor(s), that require software (e.g., firmware) to operate, but that may be absent when software is not necessary for operation.

This definition of "circuitry" applies to all uses of this term in this application, including any claims. As a further example, as used in this application, the term "circuitry" also encompasses simply a hardware circuit or processor (or processors), or a portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware implementation. The term circuitry also encompasses, for example, baseband integrated circuits, processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices, if applicable to the particular claim element.

As used herein, the term "communications network" refers to a network conforming to any suitable communications standard, such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), and Narrowband Internet of Things (NB-IoT). Furthermore, communications between terminal devices and network devices in a communications network may be conducted in accordance with any suitable generation of communications protocol, including, but not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, future fifth-generation (5G) communications protocols, and/or any other protocols now known or developed in the future. Embodiments of the present disclosure may be applied in a variety of communications systems. Given the rapid development of communications, it is natural that future communications technologies and systems will emerge in which the present disclosure may be embodied. The scope of the present disclosure should not be considered limited to only the aforementioned systems.

As used herein, an apparatus may include a terminal device, a network device, or any other suitable device. As used herein, the term "network device" refers to a node in a communication network through which a terminal device accesses and receives services from the network. A network device may refer to a base station (BS) or an access point (AP), such as a Node B (NodeB or NB), evolved Node B (eNodeB or eNB), NR NB (also referred to as gNB), remote radio unit (RRU), radio header (RH), remote radio head (RRH), repeater, low-power node such as femto, pico, etc., depending on the terminology and technology used.

The term "terminal device" refers to any end device that may be capable of wireless communication. By way of example and not limitation, a terminal device may also be referred to as a communication device, user equipment (UE), subscriber station (SS), mobile subscriber station, mobile station (MS), or access terminal (AT). Terminal devices may include, but are not limited to, mobile phones, cellular phones, smartphones, voice-over-IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices such as digital cameras, gaming terminals, music storage and playback devices, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop mounted devices (LMEs), USB dongles, smart devices, wireless customer premises equipment (CPEs), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and/or other wireless devices operating in industrial and/or automated processing chain contexts), consumer electronics devices, and devices operating in commercial and/or industrial wireless networks. In the following description, the terms "terminal device," "communications device," "terminal," "user equipment," and "UE" may be used interchangeably.

FIG. 1 illustrates an exemplary communications system 100 in which embodiments of the present disclosure can be implemented. System 100 includes two devices: a network device 110 and a terminal device 120 served by network device 110. The coverage area of network device 110 is referred to as a cell 102. It should be understood that the number of devices (both network devices and terminal devices) is for illustrative purposes only, without implying any limitation. System 100 may include any suitable number of network devices and terminal devices employed to implement embodiments of the present disclosure. Although not shown, it will be understood that one or more terminal devices may be located in cell 102 and served by network device 110.

Communications in communication system 100 may be performed according to any suitable communication protocol(s), including, but not limited to, cellular communication protocols such as first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), and fifth generation (5G), wireless local network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and/or any other protocol now known or developed in the future. Communications may also utilize any suitable wireless communication technology, including, but not limited to, code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple-input multiple-output (MIMO), orthogonal frequency division multiplexing (OFDM), cyclic prefix orthogonal frequency division multiplexing (CP-OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), and/or any other technology now known or developed in the future.

In the communication system 100, once a connection is established, the network device 110 can communicate with the terminal device 120, and the terminal device 120 can also communicate data and control information to the network device 110. The link from the network device 110 to the terminal device 120 is referred to as the downlink (DL), and the link from the terminal device 120 to the network device 110 is referred to as the uplink (UL). In the DL, the network device 110 is the transmitting (TX) device (or transmitter), and the terminal device 120 is the receiving (RX) device (or receiver). In the UL, the terminal device 120 is the TX device (or transmitter), and the network device 110 is the RX device (or receiver).

Typically, to communicate with network device 110, terminal device 120 may initiate an RA procedure to establish or re-establish a connection with network device 110.

There are several possible RA procedures that can be used, such as two-stage RA and four-stage RA. The RA procedure may be based on contention between multiple terminal devices. A four-stage contention-based RA procedure is an exemplary procedure, which is briefly introduced below with reference to FIG. 2A. In the RA procedure 200 of FIG. 2A, the terminal device selects and transmits a random access preamble (which may be referred to as "Msg1") to the network device (210). The network device then transmits a random access response RAR (which may be referred to as "Msg2") to the random access preamble (220). Upon receiving the random access response, the terminal device transmits a scheduled transmission (which may be referred to as "Msg3") to the network device (230). The network device transmits a contention resolution (which may be referred to as "Msg4") to the terminal device in response to contention across its serving terminal devices (240).

It has been agreed to use a two-stage procedure to achieve rapid random access. An example of a two-stage RA contention-based RA procedure is also briefly introduced below with reference to FIG. 2B. In the RA procedure 202 of FIG. 2B, the terminal device sends a first message (which may be referred to as "MsgA") to the network device (250). The first message combines a random access preamble (e.g., Msg1) and uplink data (e.g., Msg3). In response to the first message, the network device sends a second message (which may be referred to as "MsgB") to the terminal device (260). The second message combines a random access response (e.g., Msg2) and contention resolution (e.g., Msg4).

Conventionally, for a four-stage RA procedure, an uplink timing alignment command (TAC) is provided via an RAR scheduled on a physical downlink control channel (PDCCH) addressed to the RA radio network temporary identifier (RNTI) for all random access preamble transmissions. Because the RAR is scheduled on a PDCCH addressed to the RA-RNTI, it is possible to use a special type of medium access control protocol data unit (MAC PDU) defined solely for carrying the RAR. Contention resolution is also provided in Msg4 in the four-stage RA procedure. For terminal devices in connected mode, it is scheduled on a PDCCH scrambled with the cell-RNTI (C-RNTI), which serves as contention resolution associated with either an UL grant (contention-based random access/CBRA) or an UL grant/DL assignment (contention-free random access/CFRA).

For a two-stage RA procedure, the first message (i.e., MsgA) is a signal for UE detection, and the second message (i.e., MsgB) is for contention resolution for CBRA, which may have a payload. The first message will contain at least the equivalent information sent in Msg1/Msg3 for a four-stage RA procedure. As a baseline, all triggers for a four-stage RA procedure are also applicable to a two-stage RA procedure, although further analysis is required on how timing advances and grants can be obtained for the first message. Contention resolution in a two-stage RA procedure will be performed by including the UE identifier in the first message, which is echoed in the second message.

For the two-stage RA procedure, it is assumed that the MsgB for connected mode UEs may be similar to the four-stage RA, scheduled on the PDCCH addressed to the UE's C-RNTI. Furthermore, since connected mode UEs may also require a UL timing alignment value, it is assumed that a new Timing Advance Command (MAC CE) may be defined that may consist of a 12-bit TAC indicating the absolute value of the timing adjustment (unlike the current 6-bit TAC MAC CE, which indicates a relative adjustment to the current timing).

However, when a terminal device in connected mode performs a two-stage RA procedure by sending a first message to a network device, it cannot be assumed that contention resolution will be successful by decoding the PDCCH addressed to the C-RNTI, since the network device may, for example, successfully schedule the terminal device (e.g., DL data) after a failed scheduling request (SR) without knowing that the terminal device was performing an RA procedure. Furthermore, the requirements for the RA procedure also depend on the scenario in which the timing alignment timer (TAT) is running, i.e., whether a TAC is mandatory for the terminal device. In contrast, in a four-stage procedure, the terminal device will always receive a TAC from the RAR/Msg2.

According to some example embodiments of the present disclosure, a solution for contention resolution in an RA procedure is proposed. The solution relates to an RA procedure in which a random access preamble and a terminal device identifier are transmitted together in an RA message, such as an MsgA. One example of such an RA procedure is a two-stage RA procedure. It will be understood that any other suitable RA procedure may also be applicable. According to the solution, a device transmits a random access request to a further device, the random access request including a random access preamble and a device identifier for the random access procedure. The device also receives control information from the further device regarding a control channel addressed to the identifier, the control information indicating at least one of resource and timing information for communication between the device and the further device. The device then determines the result of the random access procedure based at least in part on the control information. In this way, the result of the RA procedure and contention resolution can be accurately determined even in the presence of other scheduling from network devices that do not respond to the RA procedure.

Several example embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. Reference is now made to FIG. 3, which illustrates a process 300 for conflict resolution in an RA procedure according to an example embodiment of the present disclosure. For purposes of discussion, process 300 will be described with reference to FIG. 1. Process 300 may involve terminal device 120 and network device 110, as shown in FIG. 1. While process 300 is described as terminal device 120 accessing network device 110, it should be understood that the roles of terminal device 120 and network device 110 may be reversed. It should also be understood that the example embodiments described herein may apply to two terminal devices, one attempting to access the other.

In process 300, the terminal device 120 transmits a random access request to the network device 110 (305). The random access request includes a random access preamble and an identifier of the terminal device 120 for the random access procedure. This random access procedure may be the two-stage RA procedure described above, and the random access request may be included in the first message, i.e., MsgA. Once the random access request is transmitted, the terminal device 120 may monitor the PDCCH for contention resolution and start a timer to monitor contention resolution from the network device 110. For purposes of discussion, this timer will hereafter be referred to as the CR timer.

In some example embodiments, the terminal device 120 may be in a connected state with the network device 110, i.e., the terminal device 120 is in a connected mode. This means that the terminal device 120 has completed its initial access to the network device 110. The identifier of the terminal device 120 may be, for example, the C-RNTI of the terminal device 120. In this case, the terminal device 120 may send a MsgA with a C-RNTI MAC CE to the network device 110.

The RA procedure may be triggered in any suitable manner. For example, the RA procedure may be initiated for beam failure recovery by a PDCCH command, by the MAC sublayer, or by the Radio Resource Control (RRC) sublayer.

Network device 110 receives a random access request from terminal device 120. If network device 110 determines that the contention-based random access for terminal device 120 is successful, network device 110 determines (310) control information to be sent to inform terminal device 120 that the random access was successful. The control information may indicate at least one of resource and timing information for communication between network device 110 and terminal device 120.

The control information may include a resource indication, e.g., a DL assignment or an UL grant. Alternatively or additionally, the control information may include a timing advance command (TAC) to indicate, e.g., a timing adjustment amount to be used for timing alignment with the terminal device 120 in the uplink. The TAC may also be transmitted by using resources indicated by the DL assignment. Determination of the control information by the network device 110 is described in more detail below.

Furthermore, the network device 110 transmits (315) control information on a control channel addressed to the identifier of the terminal device 120. For example, the control information may be transmitted in a PDCCH addressed to the C-RNTI of the terminal device 120. The network device 110 may further transmit other control information and data to the terminal device 120.

As such, the terminal device 120 may receive the control information by monitoring a control channel addressed to this identifier. For example, the terminal device 120 may receive the control information by monitoring a PDCCH addressed to this C-RNTI. Furthermore, the terminal device 120 determines the outcome of the RA procedure based at least in part on the control information (320).

A detailed description will now be given from the perspective of the terminal device 120 of how to determine the result of the RA procedure. A timing advance for uplink transmissions is mandatory. The TAC, as described above, is used to inform the terminal device 120 of a relative or absolute timing advance value for timing adjustment. Meanwhile, a timer called a timing alignment timer (TAT) may be maintained by the terminal device 120. The TAT is used to indicate whether the terminal device 120 is currently in timing alignment with the network device 110 in the uplink. If the TAT is active, it means that the terminal device 120 is currently in timing alignment with the network device 110 in the uplink. If the TAT is not active, it means that a TAC is mandatory for the terminal device 120. When the TAC is received from the network device 110, the TAT will be restarted or started.

In some example embodiments, the terminal device 120 may determine the result of the RA procedure based on control information received on a control channel. The terminal device 120 may determine whether a TAC is received from the network device 110, regardless of whether the TAT is active. The TAC may be received on a physical downlink shared channel (PDSCH), e.g., in a TAC MAC CE, or on a PDCCH as a scheduling command.

In one exemplary embodiment, the terminal device 120 may determine the result of the RA procedure based on a resource indication received on a control channel, for example, a PDCCH addressed to the C-RNTI of the terminal device 120. If the PDCCH transmission includes a DL assignment, the terminal device 120 may determine whether a TAC is received using the DL resources indicated by the DL assignment. If a TAC is received, the terminal device 120 may determine that the RA procedure and contention resolution are successful. When a TAC is received, the terminal device 120 may further restart the TAT (if the TAT is active) or start the TAT (if the TAT is not active). Alternatively, when the TAT is active, the terminal device 120 may ignore the received TAC so that the TAT is not restarted. Because the contention resolution is considered successful, the terminal device 120 may stop or abort the CR timer.

The TAC may be included in a data unit, such as a MAC protocol data unit (PDU). For example, based on the DL allocation, the terminal device 120 may decode a MAC PDU on the PDSCH. If the decoded MAC PDU includes a TAC MAC CE with an absolute timing value for the timing adjustment, the terminal device 120 may determine that the RA procedure is successful. The terminal device 120 may also stop or abort the CR timer.

Referring to FIG. 4, FIG. 4 shows a schematic diagram 400 illustrating a TAC MAC CE 401 according to some example embodiments of the present disclosure. As shown in FIG. 4, the TAC MAC CE 401 occupies 12 bits, which means that the TAC MAC CE 401 indicates an absolute timing advance value for timing adjustment. It should be understood that the TAC MAC CE shown in FIG. 4 is an example without any limitations.

In another example embodiment, the terminal device 120 may determine the result of the RA procedure based on timing information received on a PDCCH addressed to the C-RNTI of the terminal device 120. For example, if a TAC is directly conveyed by the PDCCH as a scheduling command, or if the scheduling command conveyed by the PDCCH indicates a TAC, the terminal device 120 may determine that the RA procedure is successful.

In such an embodiment, the results of the RA procedure and conflict resolution can be determined in a simple manner, which is useful for a two-stage RA procedure.

For the above embodiment in which the TAC is used by the terminal device 120 as a criterion, if there are cases in which the TAC may be sent or indicated by the network device 110 without an RA procedure, the terminal device 120 may further determine whether the TAC is a response to an RA procedure. If the terminal device 120 determines that the TAC is a response to an RA procedure, the terminal device 120 may determine that the RA procedure is successful.

By way of example, the TAC MAC CE may include a command indication indicating that the TAC MAC CE is to be sent in response to an RA procedure. Alternatively, such a command indication may not be included in the TAC MAC CE, but may instead be sent in association with the TAC MAC CE. In this way, erroneous determinations regarding the outcome of the RA procedure may be avoided.

In some example embodiments, the terminal device 120 may determine the outcome of the RA procedure based on the activation status of a TAT maintained by the terminal device 120 and control information on a control channel addressed to an identifier of the terminal device 120. The terminal device 120 may determine whether the TAT is activated.

If the TAT is not active, this means that a TAC is mandatory for the terminal device 120, and the receipt of the TAC or another indication of timing advance may be used as a criterion for contention resolution. If the TAT is not active and a TAC is received, the terminal device 120 may determine that the RA procedure is successful. The TAC may be received on the PDSCH in the form of a TAC MAC CE, as described above, or on the PDCCH as a scheduling command.

For example, based on the DL allocation received on the PDCCH addressed to the C-RNTI of the terminal device 120, the terminal device 120 may decode a MAC PDU on the PDSCH. If the decoded MAC PDU includes a TAC MAC CE with an absolute timing value for the timing adjustment, the terminal device 120 may determine that the RA procedure is successful. The terminal device 120 may also stop or abort the CR timer.

The manner in which the terminal device 120 receives or determines the TAC is similar to the above embodiment in which the TAC is used as a reference regardless of the operational state of the TAT held by the terminal device 120. Therefore, details on this point will not be repeated here.

It should be understood that in cases where a TAC may be sent or indicated by the network device 110 without an RA procedure, the terminal device 120 may further determine whether the TAC is a response to an RA procedure. If the terminal device 120 determines that the TAC is a response to an RA procedure, the terminal device 120 may determine that the RA procedure is successful.

When the TAT is active, this means that the terminal device 120 is in timing alignment with the network device 110 in the uplink, and TAC is not mandatory for the terminal device 120. Therefore, if the TAT is active and the control information received on the control channel indicates an uplink resource, the terminal device 120 may determine that the RA procedure is successful. For example, in the case where the TAT is active, if the PDCCH received by the terminal device 120 includes an UL grant, the terminal device 120 may determine that the RA procedure is successful.

It should be understood that the aspects described above with respect to various exemplary embodiments may be combined. For example, if TAT is active, a determination of whether a TAC is received or indicated may be used as a criterion for contention resolution in addition to an uplink resource indication (e.g., an UL grant).

For example embodiments in which the TAC is used as the basis for contention resolution, the TAT may be started or restarted upon receipt of the TAC, particularly the TAC MAC CE. In some example embodiments, the TAC may also be ignored if the TAT is running.

A detailed description will now be given of how the terminal device 120 determines the outcome of the RA procedure. Returning now to FIG. 3, after receiving the random access request, the network device 110 may also determine (310) the control information to be sent to the terminal device 120.

A timer similar to the TAT maintained by the terminal device 120 may be maintained by the network device 110. Such a timer is used to indicate whether the terminal device 120 is currently in timing alignment with the network device 110 on the uplink. It should be understood that the network device 110 may maintain multiple such timers for each of the terminal devices in the serving cell 102.

In some example embodiments, network device 110 may transmit a TAC to terminal device 120 regardless of the running state of a timer for terminal device 120. For example, network device 110 may determine a TAC for terminal device 120. Network device 110 may transmit a TAC MAC CE on the PDSCH and include a DL allocation in a PDCCH addressed to the C-RNTI of terminal device 120 so that the PDSCH can be detected and decoded by terminal device 120. Alternatively or additionally, network device 110 may transmit the TAC in a PDCCH addressed to the C-RNTI of terminal device 120 as a scheduling command so that terminal device 120 may receive the TAC directly on the PDCCH without decoding the PDSCH.

In some example embodiments, network device 110 may determine the control information to be transmitted to terminal device 120 further based on a timer maintained for terminal device 120. If the timer for terminal device 120 is not running, network device 110 may determine a TAC for terminal device 120 as described above and transmit a TAC for the PDCCH or PDSCH to terminal device 120.

When the timer for the terminal device 120 is running, the network device 110 may determine uplink resources for the terminal device 120 and transmit an indication of the determined uplink resources. For example, the network device 110 may transmit an UL grant for a PDCCH addressed to the C-RNTI of the terminal device 120.

It should be understood that the aspects described above with respect to the various exemplary embodiments may be combined. For example, if a timer for the terminal device 120 is running, the network device 110 may further determine a TAC for the terminal device 120 and transmit the determined TAC to the terminal device 120.

The above exemplary embodiments are described in a scenario in which a terminal device 120 is to access a network device 110. Embodiments of the present disclosure may also be applied to scenarios involving two terminal devices or two network devices, one of which is to access the other.

An exemplary embodiment according to the present disclosure is described in more detail with reference to Figures 5 and 6.

FIG. 5 illustrates a flowchart of an example method 500 according to some example embodiments of the present disclosure. Method 500 can be implemented in an apparatus, for example, terminal device 120 as shown in FIG. 1. For purposes of discussion, method 500 will be described with reference to FIG. 1.

At block 510, the terminal device 120 transmits a random access request to the network device 110, the random access request including a random access preamble and an identifier of the terminal device 120 for the random access procedure. At block 520, the terminal device 120 receives control information from the network device 110 on a control channel addressed to the identifier, the control information indicating at least one of resource and timing information for communication between the terminal device 120 and the network device 110. At block 530, the terminal device 120 determines a result of the random access procedure based at least in part on the control information.

In some example embodiments, determining the result of the random access procedure includes determining, in response to control information indicating a first resource for a first link from network device 110 to terminal device 120, whether a timing advance command for a timing adjustment amount is received by using the first resource, where the timing adjustment amount is used for timing alignment with network device 110 on a second link from terminal device 120 to network device 110, and determining that the random access procedure is successful in response to determining that the timing advance command is received.

In some example embodiments, determining the outcome of the random access procedure includes determining that the random access procedure is successful in response to control information indicating a timing advance command for a timing adjustment amount used for timing alignment with network device 110 on a second link from terminal device 120 to network device 110.

In some example embodiments, determining that the random access procedure is successful includes determining whether the timing advance command is a response to a random access request, and determining that the random access procedure is successful in response to determining that the timing advance command is a response to the random access request.

In some example embodiments, determining the result of the random access procedure includes determining the result of the random access procedure further based on determining whether a timer maintained by the terminal device 120 is running, the timer being configured to indicate whether the terminal device 120 is in timing alignment with the network device 110 on a second link from the terminal device 120 to the network device 110.

In some example embodiments, determining the outcome of the random access procedure is further based on determining that the timer has not run.

In some example embodiments, method 500 further includes starting a timer in response to determining that a timing advance command is received.

In some example embodiments, determining the outcome of the random access procedure further based on the determination includes determining that the random access procedure is successful in response to determining that the timer is running and that the control information indicates second resources for the second link.

In some exemplary embodiments, the identifier of the terminal device 120 includes a cell radio network temporary identifier of the terminal device 120.

In some exemplary embodiments, the terminal device 120 is in a connected state with the network device 110.

FIG. 6 illustrates a flowchart of an example method 600 according to some example embodiments of the present disclosure. Method 600 can be implemented in an apparatus, for example, network device 110 as shown in FIG. 1. For purposes of discussion, method 600 will be described with reference to FIG. 1.

At block 610, the network device 110 receives a random access request from the terminal device 120, the random access request including a random access preamble and an identifier of the terminal device 120 for a random access procedure. At block 620, in response to the random access request, the network device 110 determines control information indicating at least one of resource and timing information for communication between the network device 110 and the terminal device 120. At block 630, the network device 110 transmits the control information to the terminal device 120 on a control channel addressed to the identifier.

In some example embodiments, determining the control information includes determining a timing advance command for a timing adjustment amount, the timing adjustment amount being used for timing alignment with the terminal device 120 on a second link from the terminal device 120 to the network device 110; transmitting the timing advance command to the terminal device 120 by using a first resource for the first link from the network device 110 to the terminal device 120; and determining the control information based on the first resource.

In some example embodiments, determining the control information includes determining a timing advance command for a timing adjustment amount, the timing adjustment amount being used for timing alignment with the terminal device 120 on a second link from the terminal device 120 to the network device 110; and determining the control information based on the timing advance command.

In some example embodiments, the method 600 further includes indicating to the terminal device 120 that the timing advance command is a response to the random access request.

In some example embodiments, determining the control information includes determining the control information based on a determination of whether a timer maintained by the network device 110 is running, the timer being configured to indicate whether the network device 110 is in timing alignment with the terminal device 120 in a second link from the terminal device 120 to the network device 110.

In some example embodiments, method 600 further includes determining control information further based on determining that the timer is not running.

In some example embodiments, the method 600 further includes starting a timer after sending the timing advance command.

In some example embodiments, determining the control information based on the determination further includes, in response to determining that the timer is running, determining control information to indicate a second resource for the second link.

In some exemplary embodiments, the identifier of the terminal device 120 includes a cell radio network temporary identifier of the terminal device 120.

In some exemplary embodiments, the terminal device 120 is in a connected state with the network device 110.

In some example embodiments, an apparatus capable of performing method 500 (e.g., terminal device 120) may include means for performing each step of method 500. The means may be implemented in any suitable form. For example, the means may be implemented as a circuit or a software module.

In some example embodiments, the apparatus includes: means for transmitting a random access request to a second device, the random access request including a random access preamble and an identifier of the device for a random access procedure; means for receiving control information from the second device on a control channel addressed to the identifier, the control information indicating at least one of resource and timing information for communication between the apparatus and the second device; and means for determining a result of the random access procedure based at least in part on the control information.

In some example embodiments, the means for determining the result of the random access procedure includes means for determining, in response to control information indicating a first resource for a first link from the second device to the device, whether a timing advance command for a timing adjustment amount is received by using the first resource, where the timing adjustment amount is used for timing alignment with the second device in the second link from the device to the second device; and means for determining that the random access procedure is successful in response to determining that the timing advance command is received.

In some example embodiments, the means for determining the outcome of the random access procedure includes means for determining that the random access procedure is successful in response to control information indicating a timing advance command for a timing adjustment amount used for timing alignment with the second device in a second link from the device to the second device.

In some example embodiments, the means for determining that the random access procedure is successful includes means for determining whether the timing advance command is a response to a random access request, and means for determining that the random access procedure is successful in response to determining that the timing advance command is a response to the random access request.

In some example embodiments, the means for determining the outcome of the random access procedure includes means for determining the outcome of the random access procedure further based on determining whether a timer maintained by the device is running, the timer configured to indicate whether the device is in timing alignment with a second device in a second link from the device to the second device.

In some example embodiments, determining the outcome of the random access procedure is further based on determining that the timer has not run.

In some example embodiments, the apparatus further includes means for starting a timer in response to determining that a timing advance command is received.

In some example embodiments, the means for determining the outcome of the random access procedure further based on the determination includes means for determining that the random access procedure is successful in response to determining that the timer is running and the control information indicates second resources for the second link.

In some example embodiments, the device identifier includes a cell radio network temporary identifier for the device.

In some exemplary embodiments, the device is in communication with a second device.

In some example embodiments, the apparatus includes a terminal device and the second apparatus includes a network device.

In some example embodiments, an apparatus capable of performing method 600 (e.g., network device 110) may include means for performing each step of method 600. The means may be implemented in any suitable form. For example, the means may be implemented as circuitry or a software module.

In some example embodiments, the apparatus includes: means for receiving a random access request from a second device, the random access request including a random access preamble for a random access procedure and an identifier of the second device; means for determining, in response to the random access request, control information indicating at least one of resource and timing information for communication between the apparatus and the second device; and means for transmitting, to the second device, the control information on a control channel addressed to the identifier.

In some example embodiments, the means for determining the result of the random access procedure includes means for determining, in response to control information indicating a first resource for a first link from the second device to the device, whether a timing advance command for a timing adjustment amount is received by using the first resource, where the timing adjustment amount is used for timing alignment with the second device in the second link from the device to the second device; and means for determining that the random access procedure is successful in response to determining that the timing advance command is received.

In some example embodiments, the means for determining the outcome of the random access procedure includes means for determining that the random access procedure is successful in response to control information indicating a timing advance command for a timing adjustment amount used for timing alignment with the second device in a second link from the device to the second device.

In some example embodiments, the means for determining that the random access procedure is successful includes means for determining whether the timing advance command is a response to a random access request, and means for determining that the random access procedure is successful in response to determining that the timing advance command is a response to the random access request.

In some example embodiments, the means for determining the result of the random access procedure includes means for determining the result of the random access procedure further based on determining whether a timer maintained by the device is running, the timer configured to indicate whether the device is in timing alignment with a second device in a second link from the device to the second device.

In some example embodiments, determining the outcome of the random access procedure is further based on determining that the timer has not run.

In some example embodiments, the system further includes means for starting a timer in response to determining that a timing advance command is received.

In some example embodiments, the means for determining the outcome of the random access procedure further based on the determination includes means for determining that the random access procedure is successful in response to determining that the timer is running and the control information indicates second resources for the second link.

In some example embodiments, the device identifier includes a cell radio network temporary identifier for the device.

In some exemplary embodiments, the device is in communication with a second device.

In some example embodiments, the apparatus includes a terminal device and the second apparatus includes a network device.

Figure 7 is a simplified block diagram of a device 700 suitable for implementing an embodiment of the present disclosure. The device 700 may be provided to implement a communications device, such as the terminal device 120 or the network device 110 shown in Figure 1. As shown, the device 700 includes one or more processors 710, one or more memories 720 coupled to the processors 710, and one or more communications modules 740 coupled to the processors 710.

The communications module 740 is for two-way communications. The communications module 740 has at least one antenna to facilitate communications. The communications interface may represent any interface necessary for communications with other network elements.

Processor 710 may be of any type suitable for a local technology network and may include, by way of non-limiting example, one or more of the following: a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 700 may have multiple processors, such as application-specific integrated circuit chips slaved in time to a clock that synchronizes the main processor.

Memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memory include, but are not limited to, read-only memory (ROM) 724, electrically programmable read-only memory (EPROM), flash memory, hard disks, compact disks (CDs), digital video disks (DVDs), and other magnetic and/or optical storage. Examples of volatile memory include, but are not limited to, random access memory (RAM) 722 and other volatile memory that does not persist during power-down periods.

The computer program 730 includes computer-executable instructions that are executed by an associated processor 710. The program 730 may be stored in ROM 720. The processor 710 may perform any suitable actions and processes by loading the program 730 into RAM 720.

Embodiments of the present disclosure may be implemented by program 730, which may cause device 700 to perform any of the processes of the present disclosure, such as those discussed with reference to Figures 5 and 6. Embodiments of the present disclosure may also be implemented by hardware or a combination of software and hardware.

In some embodiments, the program 730 may be tangibly contained on a computer-readable medium, which may be included on the device 700 (such as in memory 720) or other storage accessible to the device 700. The device 700 may load the program 730 from the computer-readable medium into RAM 722 for execution. The computer-readable medium may include any type of tangible non-volatile storage, such as ROM, EPROM, flash memory, hard disk, CD, and DVD. Figure 8 shows an example of a computer-readable medium 800 in the form of a CD or DVD. The computer-readable medium has the program 730 stored on it.

In general, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. While various aspects of embodiments of the present disclosure are shown and described as block diagrams, flowcharts, or using other graphical representations, it should be understood that the blocks, apparatus, systems, techniques, or methods described herein may be implemented in, by way of non-limiting example, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or some combination thereof.

The present disclosure also provides at least one computer program tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as those contained in program modules, that execute on a target real or virtual processor device to perform the method 500 or 600 described above with reference to FIGS. 5-6. Generally, program modules include routines, programs, libraries, objects, classes, components, or data structures that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or divided among program modules as desired in various embodiments. The machine-executable instructions for program modules may be executed in local or distributed devices. In distributed devices, program modules may be located in both local and remote storage media.

Program code for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus such that, when executed by the processor or controller, the program code performs the functions/acts specified in the flowcharts and/or block diagrams. The program code may run entirely on the machine, partially on the machine, as a standalone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

In the context of the present disclosure, computer program code or associated data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, etc.

The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media may include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Furthermore, while operations are shown in a particular order, this should not be construed as implying that such operations must be performed in the particular order or sequence shown, or that all of the operations shown must be performed to achieve desired results. In certain situations, multitasking and parallel processing may be advantageous. Similarly, while some specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination.

Although the present disclosure has been described in language specific to structural features and/or method acts, it should be understood that the present disclosure as defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims (31)

1. A first device configured for wireless communication, the first device comprising:
at least one processor;
at least one memory for storing instructions;
wherein the instructions, when executed by the at least one processor, cause the first device to
receiving, at the first device , from a second device, control information on a control channel addressed to an identifier of the first device for a random access procedure, the control information indicating at least one of a first resource for a downlink between the second device and the first device and timing information for an uplink between the first device and the second device; and
The result of the random access procedure is calculated by at least
whether a timer maintained by the first device is running, the timer configured to indicate whether the first device is in timing alignment with the second device in the uplink between the first device and the second device;
whether a timing advance command is received using the first resource, the timing advance command indicating a timing adjustment amount to be used for timing alignment between the first device and the second device in the uplink from the first device to the second device;
To make a judgment based on
A first device that causes the 2. The first device of claim 1 , wherein the instructions stored in the at least one memory, when executed by the at least one processor, further cause the first device to perform at least: starting a timer in the first device in response to determining that the timing advance command has been received. The first device of claim 1, wherein the identifier of the first device includes a cell radio network temporary identifier of the first device. The first device of claim 3, wherein the control channel is a physical downlink control channel addressed to the cell radio network temporary identifier of the first device. The first device according to claim 1 , wherein the first device is in a connected state with the second device. The first device described in any one of claims 1 to 5, wherein the first device includes a terminal device and the second device includes a network device. A second device configured for wireless communication, the second device comprising:
at least one processor;
at least one memory for storing instructions;
A second device comprising:
The instructions, when executed by the at least one processor, cause the second device to :
transmitting, on a control channel addressed to an identifier of the first device for a random access procedure , control information from the second device to the first device indicating at least one of a first resource for a downlink from the second device to the first device and timing information for an uplink from the first device to the second device , wherein the control information transmits to the first device at least:
a timer maintained by the first device is running, the timer configured to indicate whether the first device is in timing alignment with the second device in the uplink from the first device to the second device;
whether a timing advance command has been received using the first resource, the timing advance command indicating a timing adjustment amount to be used for timing alignment between the first device and the second device in the uplink from the first device to the second device;
transmitting the control information operable to cause the random access request to be determined successful based on
A second device that causes the The instructions stored in the at least one memory, when executed by the at least one processor, cause the second device to:
receiving, at the second device, from the first device, a random access request for the random access procedure, the random access request including a random access preamble and the identifier of the first device;
determining the control information in response to receiving the random access request;
The second device of claim 7 , further comprising: The second device of claim 8 , wherein the determining the control information comprises determining a timing advance command. 9. The second device of claim 8, wherein the instructions stored in the at least one memory, when executed by the at least one processor, further cause the first device to indicate that the timing advance command is in response to the random access request. The second device of claim 7, wherein the instructions stored in the at least one memory, when executed by the at least one processor, further cause the second device to start the timer in response to the first device receiving the timing advance command from the second device. The second device of claim 7, wherein the instructions stored in the at least one memory, when executed by the at least one processor, further cause the second device to perform at least the following: determine control information indicating second resources for the second link in response to determining that the timer is running. The second device according to any one of claims 7 to 12 , wherein the first device is in a connected state with the second device. The second device according to claim 7 , wherein the second device comprises a network device and the first device comprises a terminal device. The second device of claim 7 , wherein the identifier of the first device comprises a cell radio network temporary identifier of the first device. 10. A method for wireless communication performed using the first device of claim 1, comprising :
receiving, at the first device, control information from the second device on a control channel addressed to the identifier, the control information indicating at least one of a first resource for a downlink from the second device to the first device and timing information for an uplink from the first device to the second device; and
The result of the random access procedure is calculated by at least
whether a timer maintained by the first device is running, the timer configured to indicate whether the first device is in timing alignment with the second device in the uplink between the first device and the second device;
whether a timing advance command is received using the first resource, the timing advance command indicating a timing adjustment amount to be used for timing alignment between the first device and the second device in the uplink from the first device to the second device;
To make a judgment based on
A method comprising: sending a random access request from the first device to a second device for a random access procedure, the random access request including a random access preamble and an identifier of the first device;
17. The method of claim 16, further comprising: 17. The method of claim 16 , further comprising: starting a timer at the first device in response to determining that the timing advance command has been received. 19. The method of any one of claims 16 to 18, wherein the identifier of the first device comprises a cell radio network temporary identifier of the first device. 20. The method of any one of claims 16 to 19 , wherein the control channel is a physical downlink control channel addressed to the cell radio network temporary identifier of the first device. 21. The method of any one of claims 16 to 20 , wherein the first device is in a connected state with the second device. 22. The method of any one of claims 16 to 21, wherein the first device comprises a terminal device and the second device comprises a network device. 8. A method for wireless communication performed using the second device of claim 7, comprising :
transmitting, on a control channel addressed to an identifier of the first device for a random access procedure , control information from the second device to the first device indicating at least one of a first resource for a downlink from the second device to the first device and timing information for an uplink from the first device to the second device , wherein the control information transmits to the first device at least:
whether a timer maintained by the first device is running, the timer configured to indicate whether the first device is in timing alignment with the second device in an uplink from the first device to the second device;
whether a timing advance command has been received using the first resource, the timing advance command indicating a timing adjustment amount to be used for timing alignment between the first device and the second device in the uplink from the first device to the second device;
transmitting the control information operable to cause the random access request to be determined successful based on
A method comprising: receiving, at the second device, from the first device, a random access request for a random access procedure, the random access request including a random access preamble and the identifier of the first device;
determining the control information in response to receiving the random access request;
24. The method of claim 23, further comprising: 25. The method of claim 24 , wherein the determining the control information comprises determining a timing advance command. 26. The method of claim 23, further comprising indicating that the timing advance command is in response to the random access request. 27. The method of any one of claims 23 to 26 , further comprising causing the first device to start the timer after the first device receives the timing advance command from the second device. 28. The method of claim 23, wherein the determining of the control information further comprises: determining control information indicating second resources for the second link in response to determining that the timer is running. 29. The method of any one of claims 23 to 28 , wherein the first device is in communication with the second device. 30. The method of any one of claims 23 to 29, wherein the second device comprises a network device and the first device comprises a terminal device. 31. The method of any one of claims 23 to 30, wherein the identifier of the first device comprises a cell radio network temporary identifier of the first device.